Al Shabaab militants, like the ones in this photo, have attacked an African Union military baseGetty Images

Al Shabaab fighters in Somalia claim to have killed dozens of African Union troops in an attack on a base south of Mogadishu.

The attack in Janaale, in the country's Lower Shabelle province, was confirmed to Al Jazeera by the militant group's spokesman as well as residents in the area. There has been no confirmation of the number of casualties by authorities.

"Amisom can confirm that the base is still under Amisom control. Reports that the base has been taken over and our weapons captured are false," the peacekeeping force said on its Twitter feed, without giving details on casualties.

Captain Bilow Idow, a Somali military officer based in a town near Janale, told Reuters that the militants had cut off the base by blowing up a nearby bridge.

"No reinforcement can reach there," Idow said. "There is much death and damage."

Al Shabaab is currently fighting to overthrow the Somalian government and impose a hardline Islamist regime. In July, the group claimed to have killed "dozens" of Amisom troops in a raid on Lego, 100km north west of the capital.